[mythtv-users] Transcoding issues. SD is fine, HD fails

[belcampo]

Neil Salstrom wrote:
> On Thu, Apr 15, 2010 at 12:46 PM, belcampo <belcampo at zonnet.nl> wrote:
> 
>> Yes I prefer an original one
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> 
> Ok, here is the original and transcoded.  Again, HDHomerun (ATSC) and
> 720p (720_60)
> 
> http://www.mediafire.com/?dwwd1yhyzdf
> http://www.mediafire.com/?dnowzrnkmuk
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I'm using an 'old' ffmpeg version, because current are more or less broken.

Using FFmpeg version SVN-r17923 with parameters:
ffmpeg -y -i 1021_20100415191100.mpg -acodec libfaac -ab 128k -ar 48000 
-ac 6 -vcodec libx264 -threads 0 -b 2672k -deinterlace -flags +loop 
-coder 1 -refs 2 -deblockalpha 0 -deblockbeta 0  -partitions 
+parti4x4+partp8x8+parti8x8+partb8x8 -me_method umh -subq 4 -me_range 16 
  -flags2 +dct8x8+mixed_refs -cmp +chroma -bf 0 -b_strategy 1 -g 250 
-keyint_min 25 -sc_threshold 40 -maxrate 3500k -qmin 22 -qmax 26 
-croptop 10 -cropbottom 6 -cropleft 144 -cropright 144 -aspect 992:704 
-f mpegts 1021_20100415191100.ts

and remuxing that with tsMuxerGUI, because also this ancient version 
can't write compliant MPEG-TS streams.

Alternatively you can use -f matroska, you'll save one step.
BTW. -f mp4 produces sync problems at least with this version of ffmpeg.

You can get the crop-parameters with:
mplayer 1021_20100415191100.mpg -vf cropdetect

I get
filesize 28852548 compared to 57585490 of the nuv-file, which is 50% better.

Leaving out the 'crops'

I get 30041272 which is 48% better, and encodes 9-10% slower.